joao felix,
This is one situation where, to me, talking about electricity according to Conventional or Electron current flow is NOT indifferent. Don't electrons go from 0V to Vs? If so, when the IC is sinking, electrons have to flow from 0V into the IC. Hence it is the device connected between the negative (0V) and the IC that should be switched on! Right?
After reading through this thread, I believe there are two concepts you do not understand very well.
1) What constitutes charge movement?
2) Why do we have conventional current?
I will cover these two questions below, but first you may want to read the following thread.
This is conventional vs electron theory right? - All About Circuits Forum
1) Current is the movement of charge. "Current flow" or "current movement" are malapropistic phrases. They literally mean "charge flow flow", which is redundant and ridiculous. Although many folks and publications use that term, it is a misnomer to do so. "Charge flow" is the correct terminology, or you can say "current exists", "current existence", or "current direction". Using current flow is akin to NASA saying "space walk" when we know that astronauts float in space. They should instead say extra-vehicular activity (EVA).
2) Conventional charge flow (CCF) is a
mathematical methodology, not a designation of the physical direction of charge carriers. Although it may seem intuitively correct to think of the current direction as governed by the movement of the physical charge carriers, you can really get your brain wrapped around the axle by doing so. There are just as many positive charge carriers as there are negative charge carriers in the universe, and you don't want to deal with their polarities separately. Positive charge carriers include semiconductor holes and positive ions in electrochemistry, and ofter they are moving simultaneously with negative charge carriers. The CCF method was invented by engineers to do away with that worry. CCF does not ask what the polarity of the charge carrier is. It
mathematically designates charge carriers to be positive, and their flow from the positive terminals of a voltage source to the negative terminal to be in a positive direction. After the calculation is made and a number is reached, THEN, if necessary, one can reason that if the charge carrier was positive, then the number is correct. If it is negative, then the sign of the number is flipped to designate a opposite direction. By following the CCF method, you can keep your head screwed on right and tight, and concentrate of the problem instead of the charge polarity. By the way, if Ben Franklin designated electrons to be positive, then people would be bitchin' about semiconductor holes being wrong. So to sumarize, you first perform the calculation
mathematically, then look at the charge carriers to determine the
physical direction.
As a final note, you will notice that semiconductor manufacturers and electronic equipment manufacturers mark their diodes, transisters, ammeters as if they were conducting positive charged carriers. In other words, they use the CCF method.
Dear lord, and I thought I had it figured out at last...
The Deity will not help you in this matter. The members of this forum will.
Ratch